Air cooled aero engine



7- H. c. H. TOWNEND- 2,101,724

A IR COOLED'AERO EiIGI NE Filed May 12, 1936 3 Sheets-Sheet 1 1937. H.c. H. TOWNEND 2,101,72

AIR COOLED AERO ENGINE Filed May 12, 19 52 5 Sheets-Sheefi 2 H. c. H.TOWNEND AIR COOLED AERO ENGINE Dec. 7, 193

Filed May 12, 1936 5 Sheets-Sheet 3 Patented Dec. 7, 1937 UNITED STATESPATENT OFFIQE Am GOOLED AERo ENGINE Hubert Charles Henry Townend,Teddington,

England, assignor to Boulton Paul Limited, Norfolk, England 6 Claims.

More particularly, the object is to avoid the dead air region at theback of each cylinder without the use of bafile plates which arearranged'to extend near to the rear of the cylinder and restrict theopening for the air to escape, which require a considerable differenceof pressure across the baflles to ensure an adequate flow of air andwhich therefore result in increasing the drag.

According to this invention an air deflecting member is providedcomprising at least one concave surface facing the direction of flight,facing the rear surface of the cylinder, spaced apart from vthe saidrear surface and located to one side of a center plane extending in thedirection of flight and containing the axis of the cylinder, said,surface extending approximately between said center plane and an outerplane extending in the direction of flight and tangential tothe cylinderwalls. In the case of two concave surfaces, these will be arranged oneat each side of the center plane and will extend approximate- [lybetween said center plane and outer planes .extendingin thedirection offlight tangential to the cylinder walls at diametrically opposite sides.In addition to the deflector, circulators maybe provided between therear surface of the cylinder and the deflector surface and spaced apartfrom both. a V

The invention will be described further in detail and by way of examplewith reference to the accompanying drawings in which:--

Figure 1 is a view in elevation and illustrates acylinder of anaero-engine with a device in accordance with the invention arranged inthe rear thereof, a

Figure 2 is a diagrammatic plan view of the arrangement on a somewhatenlarged scale,

Figure 3 is a corresponding view of an alternative arrangement, I

Figure 4 is a view partly in section of the nose portion of an aeroplanemodified in accordance with the invention and'showing an engine cylinderassociated with a cowling, while Figure 5 is a fragmentary view in plangenerallyillustrating the manner in which the tailpiece may be arrangedto form a fairing merging into the skin of the nose of the aer0plane,-

transverse to the cylinder axis have a form cor- ;tion. From thedrawings it will be .seen that .allel with the direction of the motionof the air flow but diverge slightly outward from their rear -20question forming as it were, a nose.

-invder, as the cylinder head is of larger diameter gs entry I for airmay be adjusted by appropriately 7 covering 8 may be arranged over thetops of the -point or breakaway points of the air flowing passagebetween the cylinder wall and the circu- 55 Aircraft Fig. 6 is a sideelevation of part of the aeroplane showing the complete assembly of, theen-- gine and deflecting members within the complete cowling of theaeroplane. t l

The barrel l of the cylinder is shown in Fig-- :5 ures 1 and 4 ashaving, as is usual, a head 2 of larger diameter than the barrel itself.

In the arrangement illustrated in these figures and in Figures 4 and 5viewed in the direction in which it will travel when in position on anaerol0 plane there are arranged two elements 3 functioning ascirculators, 'which in section on a plane responding with the distortionor elongation of the stationary vortices which will be producedbehindthe cylinder of the engine when in mothey are elongated in a directiongenerally parto theirforward portion or extremity, the forward portionor extremity of each of the elements in In applying the invention to anair cooled cylthan the barrel, and isalso as a rule partly circular andpartly irregular in shape on account of the valves, etc., the form ofthe circulators will, therefore, have to be modified to suit theconditions there. I

Thus the portion of the circulators immediately behind the cylinder,head is proportionately larger than that portion thereof which isbehind the barrel, and these two portions are run smoothly one into theother. In the rear of these two elements or circulators is arranged atail piece 4 which is generally tapered or streamlined towards the rearwhile its forward portion is constituted'by surfaces 5 having acurvature corresponding, with the adjacent surfaces of the 40 elements3. At each of its two opposite sides in the construction illustratedthere is provided an adjustable side plate 6, and the width of thepositioning the plates and thus the amount of air goingrto the backofthe cylinder may be varied. As shown in Figures 1 and 4 a roof orcirculators and thetailpiece. As shown in Figure 2 fins 9 may beprovided on the cylinder and these will function as stabilizers for thebreakway round the cylinder.

The-cooling fins on the cylinder occupy the position occupied by thenose of the circulator relative to the point of breakaway on thecylinder, the circulation will also be critical. In accordance with theinvention the breakaway point or breakaway points may be stabilized bymeans of the small fins 9 or other obstructions, i. e. rods, attached tothe cylinder or otherwise held in proximity to it, and more or less inline with'the nose or forward portion of the adjacent circulator.

By using stabilizers in this way it is found that broader air passagesmay be used and a greater flow of air induced through them, and that asatisfactory velocity distribution across the throat of the centralduct, as measured with a small Pitot tube, may be obtained. 7

Without the stabilizers in the case of the broader passages there wasfound to be a tendency for most of the air to flow round one circulatoronly, whilst small disturbances would change it over to the other. 7

In Figure 3 the circulators are omitted and a central flat plate It]leading forwardfrom the front of the tail piece to the rear of thecylinders is provided inorder to maintain the two vortices.

In Figures 4 and 5 the tailpiece is faired into and in fact forms partof the nose ll of, the aeroplane, l2 and I3 indicating the portions ofthe tailpiece where they are curved to provide an unbroken surface, [4in Figure 4 indicating the cowling associated with the engine. 7

In a twin-row radial engine, the invention would normally be applied tothe rear row of cylinders only as the front cylinders are in any caseusually adequately cooled, dueto the baflling action of the rearcylinders. V H

The circulators may be used as mixture preheaters, and may carry finsfor this purpose.

The circulators may consist of rotating members pivoted to rotate freelyby virtue ofthe circulator air flow round them or may be power driven.Their surfaces may be smooth or provided with vanes.

What I claim as my invention and desire ,to secure by Letters Patentis:-

1. The combination with an air-cooled aero engine having at least onecylinder and having a rear surface of the cylinder, said rear surfacebeing determined relative to the direction of flight, of an airdeflecting member having two concave surfaces facing the direction offlight, facing the rear surface of the cylinder, spaced apart from saidrear surface and located one at each side of a center plane extending inthe direction of flight and containing the axis of the cylinder, saidconcave surfaces extending approximately between said center plane andouter planes extending in the direction of flight and tangential to thecylinder walls at diametrically opposite sides and a forwardly extendingmember at each side of said air deflecting member and inclined slightlyto the said outer plane and adapted to receive air flowing near thecylinder and along the said outer plane and direct it to the airdeflecting member whereby it is deflected inwardly and forwardly towardthe rear of the cylinder.

2. The combination with an air-cooled aero engine having at least onecylinder and having a rear surface of the cylinder, said rear surfacebeing determined relative to the direction of flight, of an airdeflecting member having a concave surface facing the direction offlight, facing the rear surface of the cylinder, spaced apart from saidrear surface and located to one side of a center plane extending in thedirection of flight and containing the axis of the cylinder, saidsurface extending approximately between said center plane and an outerplane extending in the direction of flight and tangential tothe cylinderwall, a forwardly extending member at the outer side of the said airdeflecting member and inclined slightly to the said outer plane in orderto receive air flowingnear the cylinder and direct it to the airdeflecting member whereby it is deflected inwardly and forwardly towardthe rear of the cylinder, and a cylindroid between the rear of thecylinder and the said concave surface and spaced apart from the cylinderand said concave surface, said cylindroid having a curved surface todirect said inwardly and forwardly deflected air forwardly andoutwardly. b 1

3. The combination with an air-cooled aero engine having at least onecylinder and having a rear surface of the cylinder, said rear surfacebeing determined relative to the direction of flight, of an airdeflecting member having two concave surfaces facing'the direction offlight, facing the rear surface of the cylinder, spaced apart from saidrear surface and located one at each side of a center plane extending inthe direction of flight and containing the axis of the cylinder, saidconcave surfaces extending approximately between said center plane andouter planes extending in the direction of flight and tangential to thecylinder walls at diametrically opposite sides and a forwardly extendingmember at each side of said air deflecting member and inclined slightlyto the said outer plane and adapted to receive air flowing near thecylinder and along the said outer planes and direct it to the airdeflecting member whereby it is deflected inwardly and forwardly towardthe rear surface of the cylinder and two cylindroids, one between therear surface of the cylinder and each of said concave surfaces, saidcylindroids being spaced apart from each other and from the cylinder andfrom the said concave surfaces and having a curved surface to directsaid inwardly and forwardly deflected air forwardly and outwardly.

4. The combination with an aircooledaero engine having at least onecylinder and having a rear surface of the cylinder, said rear surfacebeing determined relative to the direction ,of flight, of an airdeflecting member having a concave surface facing the direction offlight, facing the rear surface of the cylinder, spaced apart from saidrear surface and located to one side of a center plane extending in thedirection of flight and containing the axis of the cylinder, saidsurface extending approximately between said center plane and an outerplane extending in the direction of flight and tangential to thecylinder wall and a forwardly extending member at the outer side of saidair deflecting member inclined slightly to the said outer plane in orderto receive air flowing near the cylinder along said outer plane anddirect it to the air deflecting member where it is deflected inwardlyand forwardly toward the rear of the cylinder and means at the rear ofsaid air deflecting member to prevent the formation of a secondary deadair region behind said member.

5. The combination with an air-cooled areo engine having at least onecylinder and having a rear surface of the cylinder, said rear surfacebeing deterr'ninedrelative to" the direction of flight, of an airdeflecting member having a concave surface facing the direction offlight, facing the rear surface of the cylinder, spaced apart from saidrear surface and locatedto one side of a center plane extending in thedirection of flight and containing the axis of the cylinder,saidsurfaoe-extending approximately between said center plane and anouter plane extending in the direction of flight and tangential to thecylinder wall and a forwardly extending member at .the outer side ofsaid air deflecting member inclined slightly to the said outer plane inorder to receive air flowing near the cylinder along the said outerplane and direct itto the air deflecting member whereby it its deflectedinwardly and forwardly toward the rear of the cylinder and a streamlinesurface extending rearwardly from the concave surface to prevent theformation of a secondary dead air region behind said member.

6. The combination with an air-cooled aero engine having at least onecylinder and having a rear surface of the cylinder, said rear surfacebeing determined relative to the direction of flight, of anairdeflecting member having two concave surfaces facing the direction offlight, facing the rear surface of the cylinder, spaced apart from saidrear surface and located one at each side of a center plane extending inthedirection of flight and containing the axis of the cylinder, saidconcave surfaces extending approximately between said center plane andouter planes extending in the direction of flight tangential to thecylinder walls at diametrically pposite sides, a forwardly extendingmember at each side of said air deflecting member and inclined slightlyto the said outer plane and adapted to receive air flowing near thecylinder and along the said outer plane and direct it to the airdeflecting member whereby it is deflected inwardly and forwardly towardthe rear of the cylinder and two cylindroids, one between each of saidconcave surfaces and the cylinder and spaced apart from both saidconcave surfaces and the cylinder, each cylindroid being elongated in adirection generally parallel to the direction of the main airflow butdiverging slightly outward from its rear to its forward portion to forma nose at the forward portion to act as a circulator for the airdeflected inwardly and forwardly by said concave surfaces.

HUBERT CHARLES HENRY TOWNEND.

